docs: def check_projections_path(path):
      '''
      check_projections_path(path) yields the given path after checking that it is valid and updating
        neuropythy.map_projections to include any projections found on the given path.
  
      This function is called whenever neuropythy.config['projections_path'] is edited; it should not
      generally be called directly.
      '''
      path = dirpath_to_list(path)
      tmp = load_projections_from_path(path)
      # okay, seems like it passed; go ahead and update
      global map_projections
      map_projections = pyr.pmap({h: pimms.merge(npythy_map_projections[h], tmp[h])
                                  for h in six.iterkeys(npythy_map_projections)})
      return path